The present invention relates to a storage control system including a storage controller that is connected to a host computer and performs data communication with the host computer.
A database system handling large scale data, such as a data center, manages the data using a storage control system configured separately from a host computer. This storage control system includes, for example, a disk array apparatus. A number of storage devices are arranged in arrays in the disk array apparatus, which is configured based on, for example, RAID (Redundant Array of Independent (Inexpensive) Disks). On a physical storage area provided by the storage device group, at least one logical volume, being a logical storage area, is formed, and this logical volume is provided to a host computer (more specifically, a database program that operates on the host computer), which is a host system. The host computer can write/read data to/from the logical volume by transmitting a predetermined command thereto.
It has been proposed to connect a second storage controller to the storage controller to improve the performance of the storage control system (Patent Reference 1: JP-A-2005-115506). In this case, the first storage controller can manage a storage area in the second storage apparatus as if it is a storage area in its own storage apparatus by linking this storage area to a storage area in the first storage controller. When the second storage controller is connected to the first storage controller from outside, a new storage area (virtual logical volume) is virtually set in the first storage controller to link the storage area in the first storage controller to that in the second storage controller. Thus, data exchange can be performed between the storage areas in the first and second storage controllers via the virtual logical volume. Note that Patent Reference 2 (JP-A-2005-107645) discloses a storage control system that temporarily ceases processing for input/output that the storage control system receives from the host device to avoid data destruction and input/output failures during system operation, in order to provide a storage control system in which information about the configuration of a disk array switch group is modified.